Extend the benchmarking indel set by manual review using the individual cell line sequencing data from the Sequencing Quality Control 2 (SEQC2) project.

Accurate indel calling plays an important role in precision medicine. A benchmarking indel set is essential for thoroughly evaluating the indel calling performance of bioinformatics pipelines. A reference sample with a set of known-positive variants was developed in the FDA-led Sequencing Quality Control Phase 2 (SEQC2) project, but the known indels in the known-positive set were limited. This project sought to provide an enriched set of known indels that would be more translationally relevant by focusing on additional cancer related regions. A thorough manual review process completed by 42 reviewers, two advisors, and a judging panel of three researchers significantly enriched the known indel set by an additional 516 indels. The extended benchmarking indel set has a large range of variant allele frequencies (VAFs), with 87% of them having a VAF below 20% in reference Sample A. The reference Sample A and the indel set can be used for comprehensive benchmarking of indel calling across a wider range of VAF values in the lower range. Indel length was also variable, but the majority were under 10 base pairs (bps). Most of the indels were within coding regions, with the remainder in the gene regulatory regions. Although high confidence can be derived from the robust study design and meticulous human review, this extensive indel set has not undergone orthogonal validation. The extended benchmarking indel set, along with the indels in the previously published known-positive set, was the truth set used to benchmark indel calling pipelines in a community challenge hosted on the precisionFDA platform. This benchmarking indel set and reference samples can be utilized for a comprehensive evaluation of indel calling pipelines. Additionally, the insights and solutions obtained during the manual review process can aid in improving the performance of these pipelines.

Convergent MAPK pathway alterations mediate acquired resistance to FGFR inhibitors in FGFR2 fusion-positive cholangiocarcinoma.

BACKGROUND & AIMS: There is a knowledge gap in understanding mechanisms of resistance to fibroblast growth factor receptor (FGFR) inhibitors (FGFRi) and a need for novel therapeutic strategies to overcome it. We investigated mechanisms of acquired resistance to FGFRi in patients with FGFR2-fusion-positive cholangiocarcinoma (CCA). METHODS: A retrospective analysis of patients who received FGFRi therapy and underwent tumor and/or cell-free DNA analysis, before and after treatment, was performed. Longitudinal circulating tumor DNA samples from a cohort of patients in the phase I trial of futibatinib (NCT02052778) were assessed. FGFR2-BICC1 fusion cell lines were developed and secondary acquired resistance mutations in the mitogen-activated protein kinase (MAPK) pathway were introduced to assess their effect on sensitivity to FGFRi in vitro. RESULTS: On retrospective analysis of 17 patients with repeat sequencing following FGFRi treatment, new FGFR2 mutations were detected in 11 (64.7%) and new alterations in MAPK pathway genes in nine (52.9%) patients, with seven (41.2%) patients developing new alterations in both the FGFR2 and MAPK pathways. In serially collected plasma samples, a patient treated with an irreversible FGFRi tested positive for previously undetected BRAF V600E, NRAS Q61K, NRAS G12C, NRAS G13D and KRAS G12K mutations upon progression. Introduction of a FGFR2-BICC1 fusion into biliary tract cells in vitro sensitized the cells to FGFRi, while concomitant KRAS G12D or BRAF V600E conferred resistance. MEK inhibition was synergistic with FGFRi in vitro. In an in vivo animal model, the combination had antitumor activity in FGFR2 fusions but was not able to overcome KRAS-mediated FGFRi resistance. CONCLUSIONS: These findings suggest convergent genomic evolution in the MAPK pathway may be a potential mechanism of acquired resistance to FGFRi. CLINICAL TRIAL NUMBER: NCT02052778. IMPACT AND IMPLICATIONS: We evaluated tumors and plasma from patients who previously received inhibitors of fibroblast growth factor receptor (FGFR), an important receptor that plays a role in cancer cell growth, especially in tumors with abnormalities in this gene, such as FGFR fusions, where the FGFR gene is fused to another gene, leading to activation of cancer cell growth. We found that patients treated with FGFR inhibitors may develop mutations in other genes such as KRAS, and this can confer resistance to FGFR inhibitors. These findings have several implications for patients with FGFR2 fusion-positive tumors and provide mechanistic insight into emerging MAPK pathway alterations which may serve as a therapeutic vulnerability in the setting of acquired resistance to FGFRi.

Lessons learned developing and deploying a provincial virtual mental health support during the COVID-19 pandemic.

Significant efforts have been put into implementing virtual forms of healthcare and supports since the beginning of the pandemic. However, limited information has been shared with health leaders about how this has taken place, and what can be learned from this to move forward into the future. The purpose of this article is to describe lessons learned co-designing and developing a virtual health support during the COVID-19 pandemic in the province of Saskatchewan. In this article, we anchor these lessons learned on a specific virtual health service support, "SaskWell," which offers a digital service, and aims to connect residents of the province to digital mental health supports and resources.

Supporting population mental health and wellness during the COVID-19 pandemic in Canada: protocol for a sequential mixed-method study.

INTRODUCTION: The global COVID-19 pandemic has reported to have a negative impact on the mental health and well-being of individuals around the world. Mental health system infrastructure, primarily developed to support individuals through in-person care, struggled to meet rising demand for services even prior to COVID-19. With public health guidelines requiring the use of physical distancing during the pandemic, digital mental health supports may be one way to address the needs of the population. Despite this, barriers exist in promoting and supporting access to existing and emerging digital resources. Text messaging may address some of these barriers, extending the potential reach of these digital interventions across divides that may separate some vulnerable or disadvantaged groups from essential mental health supports. Building on an existing knowledge synthesis project identifying key digital resources for improved mental health, this research will establish low-tech connections to assess need and better match access to services for those who need it most. The aim of this study is to codesign a customised two-way texting service to explore need and better align access to mental health supports for Canadians located in Saskatchewan during the COVID-19 pandemic. METHODS AND ANALYSIS: This study will be completed in Saskatchewan, Canada. For this project, the RE-AIM (reach, effectiveness, adoption, implementation, maintenance) framework will be used to support three phases of a sequential mixed-method study. An advisory committee of Saskatchewan residents will guide this work with the study team. A 10-week service will be launched to connect individuals with appropriately suited digital mental health interventions through the use of text messaging. In phase 1, implementation and prototyping will be conducted with collaborative codesign for key elements related to features of an enrolment survey and initial messaging content. Phase 2 will focus on advancing the effectiveness of the service using quantitative user data. In phase 3, an embedding approach will be used to integrate both qualitative and quantitative data collected to understand the overall acceptability, satisfaction and perceived benefit of the text messaging service. Thematic analysis and descriptive statistics will be used as analytic methods. ETHICS AND DISSEMINATION: This study has received approval from the Research Ethics Board at the University of Saskatchewan. A knowledge dissemination plan has been developed that includes traditional academic approaches such as conference presentations, and academic publications, as well as mainstream approaches such as social media, radio and dissemination through the advisory committee.

RAC1 Alterations Induce Acquired Dabrafenib Resistance in Association with Anaplastic Transformation in a Papillary Thyroid Cancer Patient.

BRAF-activating mutations are the most frequent driver mutations in papillary thyroid cancer (PTC). Targeted inhibitors such as dabrafenib have been used in advanced BRAF-mutated PTC; however, acquired resistance to the drug is common and little is known about other effectors that may play integral roles in this resistance. In addition, the induction of PTC dedifferentiation into highly aggressive KRAS-driven anaplastic thyroid cancer (ATC) has been reported. We detected a novel RAC1 (P34R) mutation acquired during dabrafenib treatment in a progressive metastatic lesion with ATC phenotype. To identify a potential functional link between this novel mutation and tumor dedifferentiation, we developed a cell line derived from the metastatic lesion and compared its behavior to isogenic cell lines and primary tumor samples. Our data demonstrated that RAC1 mutations induce changes in cell morphology, reorganization of F-actin almost exclusively at the cell cortex, and changes in cell adhesion properties. We also established that RAC1 amplification, with or without mutation, is sufficient to drive cell proliferation and resistance to BRAF inhibition. Further, we identified polyploidy of chromosome 7, which harbors RAC1, in both the metastatic lesion and its derived cell line. Copy number amplification and overexpression of other genes located on this chromosome, such as TWIST1, EGFR, and MET were also detected, which might also lead to dabrafenib resistance. Our study suggests that polyploidy leading to increased expression of specific genes, particularly those located on chromosome 7, should be considered when analyzing aggressive thyroid tumor samples and in further treatments.

Expression Analysis of Same-Patient Metachronous and Synchronous Upper Tract and Bladder Urothelial Carcinoma.

PURPOSE: We compared upper tract urothelial carcinoma (UTUC) and bladder urothelial carcinoma (BUC) in same-patient metachronous UTUC and synchronous UTUC and BUC using next-generation sequencing. MATERIALS AND METHODS: Consecutive untreated same-patient samples of UTUC and BUC were macrodissected from unstained formalin-fixed, paraffin-embedded slides after quality control. Samples were divided into 4 groups: 1) UTUC-metachronous BUC, 2) BUC-metachronous UTUC, 3) synchronous UTUC-BUC, 4) UTUC without BUC. Exclusions were inadequate clinical data or histological tumor purity <30%. Whole transcriptome RNA sequencing was performed. After quality assessment, gene expression clusters using unsupervised hierarchical consensus clustering and correlation with pertinent clinicopathologic variables, a prior RNASeq data set and other published data were performed. RESULTS: RNAseq was performed on 95 samples (UTUC=61, BUC=34) from 40 untreated patients. Unsupervised consensus clustering segregated the tumors into 2 clusters that were enriched with BASE47 basal-like or luminal-like gene expression. Almost two-thirds (61.9%) of Group 2 tumors were basal-like, while the majority of Groups 1, 3, 4 (80.6%, 70.0% and 69.6%, respectively) were luminal-like (p=0.017). Further analyses revealed that the differences in basal-like and luminal-like gene expression were associated with differential fibroblast and immune cell gene expression signatures. In all, 87.5% of metachronous tumors maintained subtype membership. CONCLUSIONS: Gene expression analysis of same-patient metachronous UTUC-BUC suggests that the majority of mUTUC developing after BUC appear more basal-like, while synchronous and initial UTUC tumors appear luminal-like. Metachronous tumors largely maintain molecular subtype membership of the initial tumor regardless of chronologic development or anatomical origin.

Whole-exome sequencing for ocular adnexal sebaceous carcinoma suggests PCDH15 as a novel mutation associated with metastasis.

Ocular adnexal sebaceous carcinoma (OASeC) is an aggressive eyelid carcinoma. Analysis of molecular-genetic drivers of this disease could reveal new prognostic markers and actionable targets for treatment. To identify somatically acquired genomic mutations in OASeC and explore their associations with metastasis, whole-exome sequencing on DNA extracted from retrospectively collected tumor samples was performed. Thirty-one patients in two orbital oncology centers with OASeC were included. Sequencing results were analyzed to detect mutations and explore their possible association with metastasis. The median patient age was 64 years. A total of 1780 candidate somatic mutations were identified with median mutation rate of 1.0/Mb (range, 0.2-13.6). The five most commonly mutated genes (as determined by MutSig; q value < 0.25) were TP53 (mutated in 22 cases), ZNF750 (13 cases), RB1 (12 cases), NOTCH1 (8 cases), and PCDH15 (5 cases). Mutations in ZNF750 or NOTCH1 pathway genes were present in 24 (77%) of the 31 cases; there was a trend toward mutual exclusivity of ZNF750 and NOTCH1 mutations. All eight tumors with NOTCH1 mutations also had TP53 and/or RB1 mutations. Four of the five PCDH15 mutations and all four PCDH15 missense mutations were identified in patients with metastatic disease, including one patient with distant metastasis and three with nodal metastasis. PCDH15 was significantly associated with metastasis (P = 0.01). We identified the most commonly mutated genes in a series of OASeCs and found a previously unreported mutation in OASeC, PCDH15 mutation, that was significantly associated with metastasis. NOTCH1 mutation is an actionable mutation; clinical trials targeting this mutation are available throughout the US and could be considered for patients with metastatic NOTCH1-mutant OASeC. TP53, ZNF750, RB1, and PCDH15 mutations are most likely loss-of-function mutations and may have diagnostic and prognostic importance.

A Deep Learning Framework for Predicting Response to Therapy in Cancer.

A major challenge in cancer treatment is predicting clinical response to anti-cancer drugs on a personalized basis. Using a pharmacogenomics database of 1,001 cancer cell lines, we trained deep neural networks for prediction of drug response and assessed their performance on multiple clinical cohorts. We demonstrate that deep neural networks outperform the current state in machine learning frameworks. We provide a proof of concept for the use of deep neural network-based frameworks to aid precision oncology strategies.

Upper tract urothelial carcinoma has a luminal-papillary T-cell depleted contexture and activated FGFR3 signaling.

Upper tract urothelial carcinoma (UTUC) is characterized by a distinctly aggressive clinical phenotype. To define the biological features driving this phenotype, we performed an integrated analysis of whole-exome and RNA sequencing of UTUC. Here we report several key insights from our molecular dissection of this disease: 1) Most UTUCs are luminal-papillary; 2) UTUC has a T-cell depleted immune contexture; 3) High FGFR3 expression is enriched in UTUC and correlates with its T-cell depleted immune microenvironment; 4) Sporadic UTUC is characterized by a lower total mutational burden than urothelial carcinoma of the bladder. Our findings lay the foundation for a deeper understanding of UTUC biology and provide a rationale for the development of UTUC-specific treatment strategies.

Sebaceous carcinoma on the arm of a 10-year-old girl.

We report a case of a 10 year-old girl diagnosed with sebaceous carcinoma of the posterior left arm. The presented case reviews the histopathological and immunohistochemical characteristics of this malignancy, including a review of the literature in pediatric patients regarding prognosis and treatment. Sebaceous carcinoma is a malignant neoplasm with sebaceous differentiation, typically occurring in the sixth-to-seventh decades of life. It most commonly arises in the periocular region. It is extremely rare in the pediatric population.

Comprehensive Genomic Characterization of Upper Tract Urothelial Carcinoma.

BACKGROUND: Upper urinary tract urothelial cancer (UTUC) may have unique etiologic and genomic factors compared to bladder cancer. OBJECTIVE: To characterize the genomic landscape of UTUC and provide insights into its biology using comprehensive integrated genomic analyses. DESIGN, SETTING, AND PARTICIPANTS: We collected 31 untreated snap-frozen UTUC samples from two institutions and carried out whole-exome sequencing (WES) of DNA, RNA sequencing (RNAseq), and protein analysis. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Adjusting for batch effects, consensus mutation calls from independent pipelines identified DNA mutations, gene expression clusters using unsupervised consensus hierarchical clustering (UCHC), and protein expression levels that were correlated with relevant clinical variables, The Cancer Genome Atlas, and other published data. RESULTS AND LIMITATIONS: WES identified mutations in FGFR3 (74.1%; 92% low-grade, 60% high-grade), KMT2D (44.4%), PIK3CA (25.9%), and TP53 (22.2%). APOBEC and CpG were the most common mutational signatures. UCHC of RNAseq data segregated samples into four molecular subtypes with the following characteristics. Cluster 1: no PIK3CA mutations, nonsmokers, high-grade

Serpiginous hypopigmentation secondary to intra-articular corticosteroid injection.

Corticosteroids have been a mainstay of therapy for the treatment of many inflammatory diseases for well over 50 years. Cutaneous side effects of local corticosteroid therapy include striae, thinning of the skin, hypopigmentation, and atrophy, which are well known complications of this treatment modality.Herein, we present an unusual cutaneous adverse side effect rarely seen in intra-articular corticosteroid injections.

Targeting Stromal Glutamine Synthetase in Tumors Disrupts Tumor Microenvironment-Regulated Cancer Cell Growth.

Reactive stromal cells are an integral part of tumor microenvironment (TME) and interact with cancer cells to regulate their growth. Although targeting stromal cells could be a viable therapy to regulate the communication between TME and cancer cells, identification of stromal targets that make cancer cells vulnerable has remained challenging and elusive. Here, we identify a previously unrecognized mechanism whereby metabolism of reactive stromal cells is reprogrammed through an upregulated glutamine anabolic pathway. This dysfunctional stromal metabolism confers atypical metabolic flexibility and adaptive mechanisms in stromal cells, allowing them to harness carbon and nitrogen from noncanonical sources to synthesize glutamine in nutrient-deprived conditions existing in TME. Using an orthotopic mouse model for ovarian carcinoma, we find that co-targeting glutamine synthetase in stroma and glutaminase in cancer cells reduces tumor weight, nodules, and metastasis. We present a synthetic lethal approach to target tumor stroma and cancer cells simultaneously for desirable therapeutic outcomes.

Direct Upregulation of STAT3 by MicroRNA-551b-3p Deregulates Growth and Metastasis of Ovarian Cancer.

3q26.2 amplification in high-grade serous ovarian cancer leads to increased expression of mature microRNA miR551b-3p, which is associated with poor clinical outcome. Importantly, miR551b-3p contributes to resistance to apoptosis and increased survival and proliferation of cancer cells in vitro and in vivo. miR551b-3p upregulates STAT3 protein levels, and STAT3 is required for the effects of miR551b-3p on cell proliferation. Rather than decreasing levels of target mRNA as expected, we demonstrate that miR551b-3p binds a complementary sequence on the STAT3 promoter, recruiting RNA polymerase II and the TWIST1 transcription factor to activate STAT3 transcription, and thus directly upregulates STAT3 expression. Furthermore, anti-miR551b reduced STAT3 expression in ovarian cancer cells in vitro and in vivo and reduced ovarian cancer growth in vivo. Together, our data demonstrate a role for miR551b-3p in transcriptional activation. Thus, miR551b-3p represents a promising candidate biomarker and therapeutic target in ovarian cancer.

Regulation of the T-box transcription factor Tbx3 by the tumour suppressor microRNA-206 in breast cancer.

BACKGROUND: The Tbx3 transcription factor is over-expressed in breast cancer, where it has been implicated in proliferation, migration and regulation of the cancer stem cell population. The mechanisms that regulate Tbx3 expression in cancer have not been fully explored. In this study, we demonstrate that Tbx3 is repressed by the tumour suppressor miR-206 in breast cancer cells. METHODS: Bioinformatics prediction programmes and luciferase reporter assays were used to demonstrate that miR-206 negatively regulates Tbx3. We examined the impact of miR-206 on Tbx3 expression in breast cancer cells using miR-206 mimic and inhibitor. Gene/protein expression was examined by quantitative reverse-transcription-PCR and immunoblotting. The effects of miR-206 and Tbx3 on apoptosis, proliferation, invasion and cancer stem cell population was investigated by cell-death detection, colony formation, 3D-Matrigel and tumorsphere assays. RESULTS: In this study, we examined the regulation of Tbx3 by miR-206. We demonstrate that Tbx3 is directly repressed by miR-206, and that this repression of Tbx3 is necessary for miR-206 to inhibit breast tumour cell proliferation and invasion, and decrease the cancer stem cell population. Moreover, Tbx3 and miR-206 expression are inversely correlated in human breast cancer. Kaplan-Meier analysis indicates that patients exhibiting a combination of high Tbx3 and low miR-206 expression have a lower probability of survival when compared with patients with low Tbx3 and high miR-206 expression. These studies uncover a novel mechanism of Tbx3 regulation and identify a new target of the tumour suppressor miR-206. CONCLUSIONS: The present study identified Tbx3 as a novel target of tumour suppressor miR-206 and characterised the miR-206/Tbx3 signalling pathway, which is involved in proliferation, invasion and maintenance of the cancer stem cell population in breast cancer cells. Our results suggest that restoration of miR-206 in Tbx3-positive breast cancer could be exploited for therapeutic benefit.

Tumor microenvironment derived exosomes pleiotropically modulate cancer cell metabolism.

Cancer-associated fibroblasts (CAFs) are a major cellular component of tumor microenvironment in most solid cancers. Altered cellular metabolism is a hallmark of cancer, and much of the published literature has focused on neoplastic cell-autonomous processes for these adaptations. We demonstrate that exosomes secreted by patient-derived CAFs can strikingly reprogram the metabolic machinery following their uptake by cancer cells. We find that CAF-derived exosomes (CDEs) inhibit mitochondrial oxidative phosphorylation, thereby increasing glycolysis and glutamine-dependent reductive carboxylation in cancer cells. Through 13C-labeled isotope labeling experiments we elucidate that exosomes supply amino acids to nutrient-deprived cancer cells in a mechanism similar to macropinocytosis, albeit without the previously described dependence on oncogenic-Kras signaling. Using intra-exosomal metabolomics, we provide compelling evidence that CDEs contain intact metabolites, including amino acids, lipids, and TCA-cycle intermediates that are avidly utilized by cancer cells for central carbon metabolism and promoting tumor growth under nutrient deprivation or nutrient stressed conditions.

Robust Selection Algorithm (RSA) for Multi-Omic Biomarker Discovery; Integration with Functional Network Analysis to Identify miRNA Regulated Pathways in Multiple Cancers.

MicroRNAs (miRNAs) play a crucial role in the maintenance of cellular homeostasis by regulating the expression of their target genes. As such, the dysregulation of miRNA expression has been frequently linked to cancer. With rapidly accumulating molecular data linked to patient outcome, the need for identification of robust multi-omic molecular markers is critical in order to provide clinical impact. While previous bioinformatic tools have been developed to identify potential biomarkers in cancer, these methods do not allow for rapid classification of oncogenes versus tumor suppressors taking into account robust differential expression, cutoffs, p-values and non-normality of the data. Here, we propose a methodology, Robust Selection Algorithm (RSA) that addresses these important problems in big data omics analysis. The robustness of the survival analysis is ensured by identification of optimal cutoff values of omics expression, strengthened by p-value computed through intensive random resampling taking into account any non-normality in the data and integration into multi-omic functional networks. Here we have analyzed pan-cancer miRNA patient data to identify functional pathways involved in cancer progression that are associated with selected miRNA identified by RSA. Our approach demonstrates the way in which existing survival analysis techniques can be integrated with a functional network analysis framework to efficiently identify promising biomarkers and novel therapeutic candidates across diseases.

The ZNF304-integrin axis protects against anoikis in cancer.

Ovarian cancer (OC) is a highly metastatic disease, but no effective strategies to target this process are currently available. Here, an integrative computational analysis of the Cancer Genome Atlas OC data set and experimental validation identifies a zinc finger transcription factor ZNF304 associated with OC metastasis. High tumoral ZNF304 expression is associated with poor overall survival in OC patients. Through reverse phase protein array analysis, we demonstrate that ZNF304 promotes multiple proto-oncogenic pathways important for cell survival, migration and invasion. ZNF304 transcriptionally regulates ß1 integrin, which subsequently regulates Src/focal adhesion kinase and paxillin and prevents anoikis. In vivo delivery of ZNF304 siRNA by a dual assembly nanoparticle leads to sustained gene silencing for 14 days, increased anoikis and reduced tumour growth in orthotopic mouse models of OC. Taken together, ZNF304 is a transcriptional regulator of ß1 integrin, promotes cancer cell survival and protects against anoikis in OC.

The Atlastin C-terminal tail is an amphipathic helix that perturbs the bilayer structure during endoplasmic reticulum homotypic fusion.

Fusion of tubular membranes is required to form three-way junctions found in reticular subdomains of the endoplasmic reticulum. The large GTPase Atlastin has recently been shown to drive endoplasmic reticulum membrane fusion and three-way junction formation. The mechanism of Atlastin-mediated membrane fusion is distinct from SNARE-mediated membrane fusion, and many details remain unclear. In particular, the role of the amphipathic C-terminal tail of Atlastin is still unknown. We found that a peptide corresponding to the Atlastin C-terminal tail binds to membranes as a parallel α helix, induces bilayer thinning, and increases acyl chain disorder. The function of the C-terminal tail is conserved in human Atlastin. Mutations in the C-terminal tail decrease fusion activity in vitro, but not GTPase activity, and impair Atlastin function in vivo. In the context of unstable lipid bilayers, the requirement for the C-terminal tail is abrogated. These data suggest that the C-terminal tail of Atlastin locally destabilizes bilayers to facilitate membrane fusion.

Cupid: simultaneous reconstruction of microRNA-target and ceRNA networks.

We introduce a method for simultaneous prediction of microRNA-target interactions and their mediated competitive endogenous RNA (ceRNA) interactions. Using high-throughput validation assays in breast cancer cell lines, we show that our integrative approach significantly improves on microRNA-target prediction accuracy as assessed by both mRNA and protein level measurements. Our biochemical assays support nearly 500 microRNA-target interactions with evidence for regulation in breast cancer tumors. Moreover, these assays constitute the most extensive validation platform for computationally inferred networks of microRNA-target interactions in breast cancer tumors, providing a useful benchmark to ascertain future improvements.